Method for cavitating fluids within a cavitation chamber using a hydraulically actuated driver

ABSTRACT

A method for forming and imploding cavities within a cavitation chamber is provided. The method uses a cavitation piston, coupled to a hydraulically actuated piston, to form the desired cavities during piston retraction and then implode the cavities during piston extension. The cavitation fluid is degassed prior to hydraulically driving cavitation within the chamber. Degassing can be performed within the cavitation chamber or within a separate degassing chamber. In one aspect, a coupling sleeve is interposed between the hydraulic driver and the cavitation chamber. Preferably the coupling sleeve is evacuated. In another aspect, a cavitation fluid circulatory system is coupled to the cavitation chamber. In-line valves on the chamber inlets allow the chamber to be isolated, when desired, from the circulatory system.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/068,080, filed Feb. 28, 2005.

FIELD OF THE INVENTION

The present invention relates generally to cavitation systems and, moreparticularly, to a method of cavitating bubbles within a cavitationchamber using a hydraulically actuated driver.

BACKGROUND OF THE INVENTION

Sonoluminescence is a well-known phenomena discovered in the 1930's inwhich light is generated when a liquid is cavitated. Although a varietyof techniques for cavitating the liquid are known (e.g., sparkdischarge, laser pulse, flowing the liquid through a Venturi tube), oneof the most common techniques is through the application of highintensity sound waves.

In essence, the cavitation process consists of three stages; bubbleformation, growth and subsequent collapse. The bubble or bubblescavitated during this process absorb the applied energy, for examplesound energy, and then release the energy in the form of light emissionduring an extremely brief period of time. The intensity of the generatedlight depends on a variety of factors including the physical propertiesof the liquid (e.g., density, surface tension, vapor pressure, chemicalstructure, temperature, hydrostatic pressure, etc.) and the appliedenergy (e.g., sound wave amplitude, sound wave frequency, etc.).

Although it is generally recognized that during the collapse of acavitating bubble extremely high temperature plasmas are developed,leading to the observed sonoluminescence effect, many aspects of thephenomena have not yet been characterized. As such, the phenomena is atthe heart of a considerable amount of research as scientists attempt tofurther characterize the phenomena (e.g., effects of pressure on thecavitating medium) as well as its many applications (e.g.,sonochemistry, chemical detoxification, ultrasonic cleaning, etc.).

Acoustic drivers are commonly used to drive the cavitation process. Forexample, in an article entitled Ambient Pressure Effect on Single-BubbleSonoluminescence by Dan et al. published in vol. 83, no. 9 of PhysicalReview Letters, the authors use a piezoelectric transducer to drivecavitation at the fundamental frequency of the cavitation chamber. Theyused this apparatus to study the effects of ambient pressure on bubbledynamics and single bubble sonoluminescence.

U.S. Pat. No. 4,333,796 discloses a cavitation chamber that is generallycylindrical although the inventors note that other shapes, such asspherical, can also be used. It is further disclosed that the chamber iscomprised of a refractory metal such as tungsten, titanium, molybdenum,rhenium or some alloy thereof and the cavitation medium is a liquidmetal such as lithium or an alloy thereof. Surrounding the cavitationchamber is a housing which is purportedly used as a neutron and tritiumshield. Projecting through both the outer housing and the cavitationchamber walls are a number of acoustic horns, each of the acoustic hornsbeing coupled to a transducer which supplies the mechanical energy tothe associated horn.

U.S. Pat. No. 5,658,534 discloses a sonochemical apparatus consisting ofa stainless steel tube about which ultrasonic transducers are affixed.The patent provides considerable detail as to the method of coupling thetransducers to the tube. In particular, the patent discloses atransducer fixed to a cylindrical half-wavelength coupler by a stud, thecoupler being clamped within a stainless steel collar welded to theoutside of the sonochemical tube. The collars allow circulation of oilthrough the collar and an external heat exchanger. The abutting faces ofthe coupler and the transducer assembly are smooth and flat. The energyproduced by the transducer passes through the coupler into the oil andthen from the oil into the wall of the sonochemical tube.

U.S. Pat. No. 5,858,104 discloses a shock wave chamber partially filledwith a liquid. The remaining portion of the chamber is filled with gaswhich can be pressurized by a connected pressure source. Acoustictransducers mounted in the sidewalls of the chamber are used to positionan object within the chamber while another transducer delivers acompressional acoustic shock wave into the liquid. A flexible membraneseparating the liquid from the gas reflects the compressional shock waveas a dilatation wave focused on the location of the object about which abubble is formed.

U.S. Pat. No. 5,994,818 discloses a transducer assembly for use withtubular resonator cavity rather than a cavitation chamber. The assemblyincludes a piezoelectric transducer coupled to a cylindrical shapedtransducer block. The transducer block is coupled via a central threadedbolt to a wave guide which, in turn, is coupled to the tubular resonatorcavity. The transducer, transducer block, wave guide and resonatorcavity are co-axial along a common central longitudinal axis. The outersurface of the end of the wave guide and the inner surface of the end ofthe resonator cavity are each threaded, thus allowing the wave guide tobe threadably and rigidly coupled to the resonator cavity.

PCT Application No. US02/16761 discloses a nuclear fusion reactor inwhich at least a portion of the liquid within the reactor is placed intoa state of tension, this state of tension being less than the cavitationthreshold of the liquid. In at least one disclosed embodiment, acousticwaves are used to pretension the liquid. After the desired state oftension is obtained, a cavitation initiation source, such as a neutronsource, nucleates at least one bubble within the liquid, the bubblehaving a radius greater than a critical bubble radius. The nucleatedbubbles are then imploded, the temperature generated by the implosionbeing sufficient to induce a nuclear fusion reaction.

PCT Application No. CA03/00342 discloses a nuclear fusion reactor inwhich a bubble of fusionable material is compressed using an acousticpulse, the compression of the bubble providing the necessary energy toinduce nuclear fusion. The nuclear fusion reactor is spherically shapedand filled with a liquid such as molten lithium or molten sodium. Apressure control system is used to maintain the liquid at the desiredoperating pressure. To form the desired acoustic pulse, apneumatic-mechanical system is used in which a plurality of pistonsassociated with a plurality of air guns strike the outer surface of thereactor with sufficient force to form a shock wave within the liquid inthe reactor. The application discloses releasing the bubble at thebottom of the chamber and applying the acoustic pulse as the bubblepasses through the center of the reactor. A number of methods ofdetermining when the bubble is approximately located at the center ofthe reactor are disclosed.

Avik Chakravarty et al., in a paper entitled Stable SonoluminescenceWithin a Water Hammer Tube (Phys Rev E 69 (066317), Jun. 24, 2004),investigated the sonoluminescence effect using a water hammer tuberather than an acoustic resonator, thus allowing bubbles of greater sizeto be studied. The experimental apparatus employed by the authorsincluded a sealed water hammer tube partially filled with the liquidunder investigation. The water hammer tube was mounted vertically to theshaft of a moving coil vibrator. Cavitation was monitored both with amicrophone and a photomultiplier tube.

Although a variety of cavitation systems have been designed, typicallythese systems operate at relatively low pressure and utilize acousticdrivers to cavitate extremely small bubbles. As a result, the amount ofenergy that can be concentrated during the process is limited. Thepresent invention overcomes these limitations by providing a system thatoperates at high pressures and that can be used to form and cavitatevery large bubbles.

SUMMARY OF THE INVENTION

The present invention provides a method for forming and implodingcavities within a cavitation chamber. The method uses a cavitationpiston, coupled to a hydraulically actuated piston, to form the desiredcavities during piston retraction and then implode the cavities duringpiston extension. The cavitation fluid is degassed prior tohydraulically driving cavitation within the chamber. Degassing can beperformed within the cavitation chamber or within a separate degassingchamber.

In at least one embodiment of the invention, a coupling sleeve isinterposed between the hydraulic driver and the cavitation chamber. Therod which links the cavitation piston to the hydraulic piston is housed,at least in part, within the coupling sleeve. The coupling sleeve helpsto prevent cross-contamination of the cavitation fluid and the hydraulicfluid. Additionally, by evacuating the coupling sleeve, a potentialsource for cavitation chamber gas leaks is minimized, if not altogethereliminated.

In at least one embodiment of the invention, a cavitation fluidcirculatory system is coupled to the cavitation chamber. In-line valveson the chamber inlets allow the chamber to be isolated, when desired,from the circulatory system.

In one preferred method of the invention, after cavitation fluiddegassing the cavitation piston is partially withdrawn from the fullyextended position. The cavitation chamber is then isolated, for examplefrom an external circulatory and/or degassing system. After chamberisolation, the cavitation piston is withdrawn to form a cavity withinthe cavitation fluid and then fully extended to implode the recentlyformed cavity.

In another preferred method of the invention, after cavitation fluiddegassing the cavitation piston is completely withdrawn. After pistonwithdrawal, the cavitation chamber is opened to the circulatory and/ordegassing system if previously closed, or left open if previously open.Once equilibrium has been reached, the chamber is isolated and thecavitation piston is fully extended, thereby compressing the cavitationfluid contained within the isolated chamber. After cavitation fluidcompression, the cavitation chamber is partially opened, for example tothe circulatory and/or degassing system, the amount and time that thechamber is opened to the external system sufficient to change theinternal chamber pressure by a predetermined amount. The amount that thechamber is allowed to change governs the size of the cavity that will becavitated during the cavitation process. Once the internal chamberpressure has been allowed to change by the predetermined amount, thecavitation chamber is isolated from the circulatory and/or degassingsystem. After chamber isolation, the cavitation piston is withdrawn toform a cavity within the cavitation fluid and then fully extended toimplode the recently formed cavity.

A further understanding of the nature and advantages of the presentinvention may be realized by reference to the remaining portions of thespecification and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual illustration of the principal elements of theinvention implemented in an exemplary embodiment;

FIG. 2 is a perspective view of the external body portion of acylindrical cavitation chamber for use with the invention;

FIG. 3 is a cross-sectional view of the cavitation chamber shown in FIG.2 coupled to the hydraulic driver; and

FIG. 4 is a cross-sectional view of a spherical cavitation chamber foruse with the invention.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

System Overview

FIG. 1 is a conceptual illustration of the principal elements of theinvention implemented in an exemplary embodiment. The principalcomponent of system 100 is the cavitation chamber 101. Although asillustrated cavitation chamber 101 is spherical, it will be appreciatedthat the invention is not so limited and that cavitation chambers ofother configurations (e.g., cylindrical, conical, cubical, rectangular,etc.) can also be used with the present invention. Chamber 101 must befabricated to withstand high operating pressures, preferably pressuresof at least 1,000 PSI, more preferably pressures of at least 10,000 PSI,and still more preferably pressures of at least 100,000 PSI.Additionally, chamber 101 should be designed to properly seal whenevacuated, thus allowing degassing procedures to be performed in situ.One method of fabricating chamber 101 is described in detail inco-pending U.S. patent application Ser. No. 10/925,070, filed Aug. 23,2004, entitled Method of Fabricating a Spherical Cavitation Chamber, theentire disclosure of which is incorporated herein for any and allpurposes. Alternately, for example, the chamber can be fabricated frommultiple pieces (e.g., two sections) that are bolted together with aplurality of bolts. One or more seals (e.g., o-rings, gaskets, etc.)seal the portions together, thus allowing the chamber to operate at thedesired pressures.

Chamber 101 can be fabricated from any of a variety of materialsalthough there are some constraints placed on the chamber material.First, the material is preferably machinable, thus simplifying thefabrication process. Second, the material should be conducive to highpressure operation. Third, if the chamber is to be operated at a hightemperature, the chamber material should have a relatively high meltingtemperature. Additionally, depending upon the process used to assembleindividual chamber pieces together (e.g., brazing), a high meltingtemperature may be desirable as an aid to fabrication and assembly.Fourth, the chamber material should be corrosion resistant, thusallowing the chamber to be used repeatedly and with a variety ofliquids. Fifth, the material should be hard enough to allow a goodsurface finish to be obtained. In one preferred embodiment of theinvention, the chamber is fabricated from 17-4 precipitation hardenedstainless steel.

With respect to the dimensions of the chamber, both inner and outerdimensions, the selected sizes depend upon the intended use of thechamber. For example, smaller chambers are typically preferable forsituations in which it is desirable to limit the amount of cavitatingmedium, for example due to the cost of the medium, or when extremelyhigh peak pressures are desired. On the other hand large chambers, withinside dimensions on the order of 8-10 inches or greater, simplifyexperimental set-up and event observation, and allow for implosion oflarger cavities. Thick chamber walls are preferable, both due to thehigh operating pressures encountered during chamber operation and as ameans of simplifying the coupling of the hydraulic driver to the chamberas described in detail below.

As described more fully below, the cavitation medium is degassed priorto the use of the hydraulic driver of the invention. Degassing thecavitation fluid is crucial in order for the collapsing bubbles withinthe cavitation chamber to achieve the desired high velocities, and thushigh temperatures and pressures at implosion stagnation. Although thecavitation medium can be degassed prior to filling the chamber,preferably the chamber is coupled to a circulatory system in which thereis a degassing station. For example, the system shown in FIG. 1 includesa degassing chamber 103 which is coupled to a vacuum pump 105 via athree-way valve 107, valve 107 allowing chamber 103 to be coupled eitherto pump 105 (e.g., for degassing purposes) or open to the atmosphere viaconduit 109. Degassing chamber 103 is coupled to cavitation chamber 101via cavitation chamber inlets 111 and 113. Inlets 111 and 113 arepreferably located at the top and bottom portions, respectively, ofchamber 101, and more preferably located at the uppermost and lowermostportions of chamber 101, thereby preventing bubbles from being trappedwithin chamber 101.

Although there are a variety of ways in which the degassing system canbe coupled to chamber 101, it will be appreciated that the invention isnot limited to a particular configuration. For example, degassingchamber 103 need not be coupled to chamber 101 via a pair of inlets.Rather, chamber 103 can be coupled via a single inlet, allowing thecavitation fluid to be degassed and used to fill cavitation chamber 101.The degassing chamber 103 can also be coupled to the cavitation chamber101 using a circulatory system that not only simplifies degassing, butalso cavitation chamber filling and draining. Other components that mayor may not be coupled to the circulatory system include bubble traps,cavitation fluid filters, and heat exchange systems. Further descriptionof some of these variations are provided in co-pending U.S. patentapplication Ser. Nos. 10/961,353, filed Oct. 7, 2004, and 11/001,720,filed Dec. 1, 2004, the disclosures of which are incorporated herein forany and all purposes.

Attached to chamber 101 is at least one hydraulic driver 115 that iscoupled to a hydraulic system 117. Hydraulic driver 115 includes apiston 119. As hydraulic driver 115, and thus piston 119, is withdrawn,a cavity is formed within the cavitation medium contained in chamber101. After the cavity is formed, driver 115 and thus piston 119 areextended, compressing the cavity and causing the desired cavityimplosion.

Cavitation Fluid Preparation

In order to achieve high intensity cavity implosions, the cavitationmedium must first be degassed. It should be understood that the presentinvention is not limited to a particular degassing technique, and thetechniques described herein are for illustrative purposes only.

The first step in the degassing method is to fill the degassingreservoir with cavitation fluid. Although in the illustrated embodimenta separate degassing chamber 103 coupled via a circulatory system isincluded, degassing can be performed in a separate, non-coupled chamber,or within cavitation chamber 101. In the illustrated example, the fluidwithin the reservoir is then degassed using vacuum pump 105. The amountof time required during this step depends on the volume of cavitationchamber 101, the volume of cavitation fluid to be degassed and thecapabilities of the vacuum system. Preferably vacuum pump 105 evacuatesreservoir 103 until the pressure within the reservoir is close to thevapor pressure of the cavitation fluid, for example to a pressure ofwithin 0.2 psi of the vapor pressure of the cavitation fluid or morepreferably to a pressure of within 0.02 psi of the vapor pressure of thecavitation fluid. Typically this step of the degassing procedure isperformed for at least 1 hour, preferably for at least 2 hours, morepreferably for at least 4 hours, and still more preferably until thereservoir pressure is as close to the vapor pressure of the cavitationfluid as previously noted.

Once the fluid within reservoir 103 is sufficiently degassed usingvacuum pump 105, preferably further degassing is performed by cavitatingthe fluid, the cavitation process tearing vacuum cavities within thecavitation fluid. As the newly formed cavities expand, gas from thefluid that remains after the initial degassing step enters into thecavities. During cavity collapse, however, not all of the gas re-entersthe fluid. Accordingly a result of the cavitation process is the removalof dissolved gas from the cavitation fluid via rectified diffusion andthe generation of bubbles.

Cavitation as a means of degassing the fluid can be performed withincavitation chamber 101, degassing chamber 103, or a separatecavitation/degassing chamber (not shown). Furthermore, any of a varietyof techniques can be used to cavitate the fluid. In the preferredembodiment of the invention, one or more acoustic drivers 121 arecoupled to degassing chamber 103 and/or the hydraulic chamber 101 (notshown). Acoustic drivers can be fabricated and mounted, for example, inaccordance with co-pending U.S. patent application Ser. No. 10/931,918,filed Sep. 1, 2004, the disclosure of which is incorporated herein forany and all purposes. The operating frequency of drivers 121 depends ona variety of factors such as the sound speed of the liquid within thechamber, the shape/geometry of the chamber, the sound field geometry ofthe drivers, etc. In at least one embodiment the operating frequency iswithin the range of 1 kHz to 10 MHz. The selected frequency can be theresonant frequency of the chamber, an integer multiple of the resonantfrequency, a non-integer multiple of the resonant frequency, orperiodically altered during operation.

For high vapor pressure liquids, preferably prior to theabove-identified cavitation step the use of the vacuum pump (e.g., pump105) is temporarily discontinued. Next the fluid within chamber 103 iscavitated for a period of time, typically for at least 5 minutes andpreferably for more than 30 minutes. The bubbles created during thisstep float to the top of chamber 103 due to their buoyancy. The gasremoved from the fluid during this step is periodically removed from thereactor system, as desired, using vacuum pump 105. Typically vacuum pump105 is only used after there has been a noticeable increase in pressurewithin chamber 103, preferably an increase of at least 0.2 psi over thevapor pressure of the cavitation fluid, alternately an increase of atleast 0.02 psi over the vapor pressure of the cavitation fluid, oralternately an increase of a couple of percent of the vapor pressure.Preferably the use of cavitation as a means of degassing the cavitationfluid is continued until the amount of dissolved gas within thecavitation fluid is so low that the fluid will no longer cavitate at thesame cavitation driver power. Typically these cavitation/degassing stepsare performed for at least 12 hours, preferably for at least 24 hours,more preferably for at least 36 hours, and still more preferably for atleast 48 hours.

The above degassing procedure is sufficient for most applications,however in an alternate embodiment of the invention another stage ofdegassing is performed prior to cavitating the fluid using the hydraulicactuated driver. The first step of this additional degassing stage is toform cavities within the cavitation fluid contained in the degassingchamber. These cavities can be formed using any of a variety of means,including neutron bombardment, focusing a laser beam into the cavitationfluid to vaporize small amounts of fluid, by locally heating smallregions with a hot wire, or by other means. Once one or more cavitiesare formed within the cavitation fluid, acoustic drivers 121 cause thecavitation of the newly formed cavities, resulting in the removal ofadditional dissolved gas within the fluid and the formation of bubbles.The bubbles, due to their buoyancy, drift to the top of the chamberwhere the gas can be removed, when desired, using vacuum pump 105. Thisstage of degassing can continue for either a preset time period (e.g.,greater than 6 hours and preferably greater than 12 hours), or until theamount of dissolved gas being removed is negligible as evidenced by thepressure within the chamber remaining stable at the vapor pressure ofthe cavitation fluid for a preset time period (e.g., greater than 10minutes, or greater than 30 minutes, or greater than 1 hour, etc.).

Cavitation Chambers

FIGS. 2-3 illustrate a preferred embodiment of a cavitation chamber 200in accordance with the invention. Chamber 200 can be coupled to adegassing system as shown in FIG. 1, or an alternate system aspreviously noted. To simplify fabrication, preferably chamber 200 isfabricated from a single block of material 201, for example stainlesssteel. A cylindrical hole 203 is bored into block 201, hole 203 makingup the interior portion of the cavitation chamber. A pair of end caps205/206 seal chamber 200, the end caps preferably bolted to block 2001with a plurality of bolts and sealed with one or more sealing members(e.g., o-rings, gaskets, etc.). In this embodiment of the invention, thecylindrical cavitation chamber 200 is 6 inches long with an insidediameter (ID) of 3 inches.

In the illustrated embodiment and as shown in the cross-sectional viewof FIG. 3, a hole 301 is bored into the side of chamber wall 201 suchthat it intersects a lower portion of the cavitation chamber. Althoughthis configuration is preferred, it should be understood that thehydraulic driver does not have to be coupled at a specific angle or at aspecific location relative to the cavitation chamber in order to drivecavitation within the chamber.

Within hole 301 is cavitation drive piston 303, piston 303 having anoutside diameter (OD) of 0.690 inches in this embodiment. One or moreseals 305 prevent leakage of the cavitation medium around piston 303throughout the piston stroke. In the preferred embodiment, cavitationdrive piston 303 is coupled to a hydraulically actuated piston 307 via atwo-part piston rod, i.e., rod portions 309 and 311. The two-part pistonrod design simplifies assembly/disassembly as well as systemmaintenance. Furthermore, in terms of research and development devices,this design allows a single hydraulic piston to be easily coupled to anyof a variety of cavitation chambers and cavitation pistons, thusproviding system flexibility at minimal cost. Lastly, this arrangementprovides a simple method of altering the pressure applied by piston 303to the cavitation medium. Specifically, since the peak applied pressureis directly proportional to the effective area of the piston, pressurechanges can be made by altering the ratio of the areas of hydraulicpiston 307 and cavitation drive piston 303.

Due to the need to accommodate piston 303 from full extension to fullretraction, i.e., the piston stroke, either the wall thickness ofchamber housing 201 must be appropriately sized or an additional sleeve(i.e., a spacer) must be added to accommodate the piston stroke. In theillustrated embodiment, with a piston stroke of 3 inches, a couplingsleeve 313 is introduced between housing 201 and hydraulic cylinder 311.In addition to being more economical than sizing chamber 201 toaccommodate the entire piston stroke, coupling sleeve 313 providesfurther separation between the hydraulic liquid driving the hydraulicpiston (e.g., piston 307) and the cavitation fluid within the chamber,thus helping to prevent contamination of either fluid by the other fluiddue to a faulty seal. Preferably coupling sleeve is coupled to a vacuumpump 315, thus allowing the sleeve to be evacuated. The inventor hasfound that by evacuating sleeve 313 air leakage into chamber 200 isreduced, air leakage leading to a weakening of the desired cavitationimplosions.

Although not required, in the preferred embodiment coupling sleeve 313is counter-bored into housing 201 and subsequently welded in place.Alternate methods of coupling sleeve 313 to housing 201 include bolts, athreaded hole/collar arrangement, brazing, bonding, etc. Hydrauliccylinder housing 317 is threadably coupled to sleeve 313 and held inplace via a plurality of bolts 319. A suitable hydraulic cylinder 317 ismanufactured by Ortman, for example Ortman 3T-NQ with a 2.5 inch bore, 3inch stroke and 0.625 inch piston rod.

Hydraulic cylinder 317 is coupled to a valve 321 (e.g., Continental highflow solenoid operated valves) by hydraulic lines 323/325. Valve 321applies forward pressure to piston 307 through hydraulic lines 323, thuscausing piston 307 and coupled piston 303 to become extended. Retractionof piston 307 and coupled piston 303 is caused by valve 321 applyingbackward pressure via hydraulic lines 325. Although a single hydraulicline 323 and a single hydraulic line 325 can be used to extend andretract piston 307, utilizing multiple lines 323/325 allow for morerapid extension/retraction of the pistons. Rapid extension of thepistons is further aided by the use of a nitrogen loaded, bladder typeaccumulator 327. Valve 321 is also coupled to a hydraulic pump 329(e.g., Bosch vane type pump) and a reservoir 331.

FIG. 4 is a cross-sectional view of an alternate cavitation chamber. Thedegassing aspects as well as the hydraulic cavitation driver are thesame as previously described relative to chamber 200. In thisembodiment, however, cylindrical chamber 200 is replaced with aspherical chamber 400. Spherical chamber 400 can be fabricated asdescribed in co-pending U.S. patent application Ser. No. 10/925,070,filed Aug. 23, 2004, the disclosure of which is incorporated herein forany and all purposes. Alternately, spherical chamber 400 can befabricated from multiple portions bolted together, or otherwise joined,and sealed with one or more seals (e.g., o-rings, gaskets, etc.).Operation of chamber 400 is the same as described relative to chamber200.

Hydraulic Driver Methodology

In a preferred approach, prior to cavitation and after the cavitationfluid has been degassed as previously noted, hydraulic piston 307 andcoupled cavitation piston 303 are partially withdrawn from thecompletely extended position. The amount of piston withdrawal depends,in part, on the compressibility of the cavitation medium. For example, acavitation fluid comprised of a very non-compressible liquid (e.g.,liquid metal) typically requires much less pre-cavitation pistonwithdrawal than a more compressible liquid (e.g., acetone). For acompressible liquid such as acetone, a pre-cavitation piston withdrawalof approximately 25 percent is preferred.

The next step is to isolate the cavitation chamber from any degassingsystems and/or a cavitation fluid circulatory systems to which it iscoupled. For example, assuming chamber 200 includes a pair of inlets333/335 in order to couple the chamber to a cavitation fluid circulatoryand degassing system as shown in FIG. 1, a pair of shut-off valves337/339 provide the necessary means of isolating the chamber. Chamber200 must be isolated prior to operation to insure that the desiredoperating pressures can be reached

After chamber isolation, hydraulic piston 307 and coupled cavitationpiston 303 are withdrawn, causing a cavity (e.g., a bubble) to be formedwithin the degassed cavitation fluid. The hydraulic piston 307 andcoupled cavitation piston 303 are then rapidly extended to the fullestpossible extent as limited either by mechanical piston stops or by theresultant back pressure. During piston extension, the previously createdcavity or cavities are compressed, causing cavity implosion. Subsequentcavitation cycles only require cycling cavitation piston 303, i.e., itis unnecessary to open the chamber, partially withdraw the piston,isolate the chamber and cycle the piston. Although the system can beused for single cavitation cycles, preferably multiple cycles areperformed, thus generating high chamber pressures and extremelyenergetic implosions. The maximum cycle rate depends on the speed of thesolenoid valves, the compressibility of the cavitation fluid, thepressure applied by the cavitation piston, the size of the chamber, thenumber of hydraulic lines coupling valves 321 to cylinder 317 and thesize of accumulator 315. In the preferred embodiment, pistons 307/303are fully extended at a rate of approximately 0.1 seconds per stroke.The system can be cycled, i.e., piston retracted and then extended, at arate of up to 20 cycles per second.

In an alternate preferred approach, prior to cavitation and after thecavitation fluid has been degassed, hydraulic piston 307 and coupledcavitation piston 303 are completely withdrawn. During this step thecavitation chamber can either be open to, or isolated from, any coupleddegassing and/or cavitation fluid circulatory systems. After pistons307/303 are completely withdrawn, the cavitation chamber inlets (e.g.,inlets 333/335 controlled via valves 337/339) are opened if previouslyclosed, or left open if previously open.

The next step is to isolate the cavitation chamber from any coupleddegassing and/or cavitation fluid circulatory systems, for example byclosing any inlet valves (e.g., valves 337/339 in FIG. 3). Once thechamber is isolated, hydraulic piston 307 and coupled cavitation piston303 are fully extended. As a result of the extension of pistons 307/303,the cavitation fluid is compressed and the internal pressure of thecavitation chamber is increased.

After chamber isolation and cavitation fluid compression, the cavitationchamber is partially opened to the degassing system and/or cavitationfluid circulatory system to which it is coupled. Preferably this step isperformed by opening a valve located near the top of cavitation chamber101, and more preferably at the uppermost portion of the cavitationchamber (e.g., valve 337). The valve is only opened by a small degreeand for a short period of time; just sufficient to change the internalcavitation chamber pressure by a predetermined amount. The amount thatthe pressure is allowed to change governs the size of the cavity thatwill be cavitated during the cavitation process, i.e., greater pressurechanges result in larger cavities. It will be appreciated that theinvention does not require a specific cavity size, rather the size to becavitated is dictated by the type of desired reaction and thus theintended reactants and the desired temperature and pressure. Otherfactors which determine the desired pressure change include cavitationfluid compressibility, cavitation chamber size, hydraulic drivercapabilities, cavitation piston effective area, and the degree to whichthe cavitation fluid has been degassed during the prior degassing steps.

Once the pressure has been allowed to change by the predeterminedamount, the cavitation chamber is once again isolated from the degassingand/or cavitation fluid circulatory systems. After chamber isolation,hydraulic piston 307 and coupled cavitation piston 303 are withdrawn,causing a cavity (e.g., a bubble) to be formed within the degassedcavitation fluid. The hydraulic piston 307 and coupled cavitation piston303 are then rapidly extended to the fullest possible extent as limitedeither by mechanical piston stops or by the resultant back pressure.During piston extension, the previously created cavity or cavities arecompressed, causing cavity implosion. Subsequent cavitation cycles onlyrequire cycling cavitation piston 303, i.e., it is unnecessary toopen/close the cavitation chamber and adjust the internal chamberpressure. As in the previous method, the system can be used either forsingle cavitation cycles or multiple cavitation cycles, the maximumcycle rate depending on the speed of the solenoid valves, thecompressibility of the cavitation fluid, the pressure applied by thecavitation piston, the size of the chamber, the number of hydrauliclines coupling valves 321 to cylinder 317 and the size of accumulator315.

As will be understood by those familiar with the art, the presentinvention may be embodied in other specific forms without departing fromthe spirit or essential characteristics thereof. Accordingly, thedisclosures and descriptions herein are intended to be illustrative, butnot limiting, of the scope of the invention which is set forth in thefollowing claims.

1. A method of cavitating a cavitation fluid within a cavitationchamber, the method comprising the steps of: coupling the cavitationchamber to a cavitation fluid circulatory system; degassing thecavitation fluid; retracting a cavitation piston coupled to a hydraulicdriver and coupled to the cavitation chamber, wherein said cavitationpiston is retracted to a fully withdrawn position; isolating thecavitation chamber, wherein said isolating step decouples the cavitationchamber from said cavitation fluid circulatory system; extending thecavitation piston from said fully withdrawn position to a fully extendedposition; partially coupling the cavitation chamber to said cavitationfluid circulatory system; isolating the cavitation chamber from saidcavitation fluid circulatory system after a predetermined pressure isreached; retracting said cavitation piston from said fully extendedposition to form at least one cavity within the cavitation fluid withinthe cavitation chamber; and extending the cavitation piston to implodesaid at least one cavity.
 2. The method of claim 1, further comprisingthe steps of: isolating the cavitation chamber from said cavitationfluid circulatory system prior to said first cavitation pistonretracting step; and coupling the cavitation chamber to said cavitationfluid circulatory system after said first cavitation piston retractingstep.
 3. The method of claim 1, further comprising the step ofinterposing a coupling sleeve between the cavitation chamber and saidhydraulic driver.
 4. The method of claim 1, further comprising the stepof evacuating a coupling sleeve interposed between the cavitationchamber and said hydraulic driver.
 5. The method of claim 4, whereinsaid evacuating step is performed prior to said first cavitation pistonretracting step.
 6. The method of claim 1, further comprising the stepof reducing cross-contamination of the cavitation fluid and a hydraulicfluid within the hydraulic driver with a coupling sleeve interposedbetween the cavitation chamber and said hydraulic driver.
 7. The methodof claim 1, further comprising the step of pumping the cavitation fluidfrom a degassing chamber to the cavitation chamber after completion ofsaid degassing step.
 8. The method of claim 1, said degassing stepfurther comprising the step of evacuating a degassing chamber containingthe cavitation fluid.
 9. The method of claim 1, said degassing stepfurther comprising the steps of acoustically cavitating the cavitationfluid to remove gas from the cavitation fluid, and periodically removingthe gas from said cavitation fluid circulatory system.
 10. The method ofclaim 1, said degassing step further comprising the steps ofacoustically cavitating the cavitation fluid within the cavitationchamber to remove gas from the cavitation fluid, and periodicallyevacuating the cavitation chamber to remove the gas generated by thestep of acoustically cavitating the cavitation fluid.
 11. A method ofcavitating a cavitation fluid within a cavitation chamber, the methodcomprising the steps of: coupling the cavitation chamber to a cavitationfluid degassing system; degassing the cavitation fluid; filling thecavitation chamber with the cavitation fluid; retracting a cavitationpiston coupled to a hydraulic driver and coupled to the cavitationchamber, wherein said cavitation piston is retracted to a fullywithdrawn position; isolating the cavitation chamber, wherein saidisolating step decouples the cavitation chamber from said cavitationfluid degassing system; extending the cavitation piston from said fullywithdrawn position to a fully extended position; partially coupling thecavitation chamber to said cavitation fluid degassing system; isolatingthe cavitation chamber from said cavitation fluid degassing system aftera predetermined pressure is reached; retracting said cavitation pistonfrom said fully extended position to form at least one cavity within thecavitation fluid within the cavitation chamber; and extending thecavitation piston to implode said at least one cavity.
 12. The method ofclaim 11, further comprising the steps of: isolating the cavitationchamber from said cavitation fluid degassing system prior to said firstcavitation piston retracting step; and coupling the cavitation chamberto said cavitation fluid degassing system after said first cavitationpiston retracting step.
 13. The method of claim 11, further comprisingthe step of interposing a coupling sleeve between the cavitation chamberand said hydraulic driver.
 14. The method of claim 11, furthercomprising the step of evacuating a coupling sleeve interposed betweenthe cavitation chamber and said hydraulic driver.
 15. The method ofclaim 14, wherein said evacuating step is performed prior to said firstcavitation piston retracting step.
 16. The method of claim 11, furthercomprising the step of reducing cross-contamination of the cavitationfluid and a hydraulic fluid within the hydraulic driver with a couplingsleeve interposed between the cavitation chamber and said hydraulicdriver.
 17. The method of claim 11, said degassing step furthercomprising the step of evacuating a degassing chamber containing thecavitation fluid, said degassing chamber incorporated within saidcavitation fluid degassing system.
 18. The method of claim 17, saiddegassing step further comprising the steps of acoustically cavitatingthe cavitation fluid within said degassing chamber to remove gas fromthe cavitation fluid, and periodically evacuating said degassingchamber.
 19. The method of claim 11, further comprising the steps ofacoustically cavitating the cavitation fluid within the cavitationchamber and periodically evacuating the cavitation chamber, wherein theacoustically cavitating and periodically evacuating steps are performedprior to performing said first cavitation piston retracting step.